In the manufacture of ethylene dichloride (1,2-dichloroethane or EDC) by oxychlorination of ethylene, chloral (trichloroacetaldehyde) is a by-product which is highly corrosive and must be removed prior to condensation of the reactor efluent. U.S. Pat. No. 3,488,398, assigned to B. F. Goodrich, to a method of preparing EDC (1,2-dichloroethane) employs a hot quench (70.degree.-100.degree. C) under pressure to remove excess HCl, most of the chloral and some water of reaction; the remaining gases are cooled to 0.degree.-40.degree. C to condense the remaining water and EDC. The chloral is decomposed in the hot quench by raising the pH of water to about 10 by adding an alkali or alkaline earth oxide, hydroxide or other alkaline substance to the quench water. The process for making EDC described therein is a single-pass non-recycle process.
The present invention, to the contrary, involves recycle of the non-condensible gases which includes CO.sub.2. Thus, it is important to retain the CO.sub.2 in the system.